In many instances, steps or methods of heating components or devices, such as the heating of electronic components during various fabrication processes, are included in assembly lines and the like. The heating process may include a relatively high heat for an extended period of time, a plurality of steps requiring different temperatures, etc. In the past, ovens for heating processes were generally horizontal and required large or extended areas of an assembly line. Also, because of the large horizontal area, it was difficult and expensive to maintain a desired temperature in these ovens.
To reduce the amount of area required by heating ovens in assembly lines and the like, some vertical ovens have been developed. A major problem with vertical ovens is that the heat generated within the oven tends to rise so that the upper portions of the oven are substantially hotter than the lower portions of the oven. Thus, it can be seen that temperatures within vertical ovens are very difficult to control.
A second problem with vertical ovens is the movement of components or devices through the oven. Conveyor belts and the like must be vertical to provide the vertical movement and include many moving parts which can generate particulates. Any dirt or particles worn from the conveyor system will generally fall directly into the components or devices being heated or contaminate the whole system. To overcome this problem, some vertical ovens have been devised with a system that steps the components or devices through the oven. However, these systems have a problem in that they generally must be included within the oven and are, therefore, heated as the oven is heated. As the systems are heated and cooled they expand and this expansion can dramatically change the length of steps that the components or devices are moved and can have a deleterious effect on the operation of the oven. Furthermore, these stepped systems still incorporate moving parts which are in contact and which can generate particulates within the oven. While superior to previous systems, it is desirable to eliminate anything which generates particulates.
Accordingly it is highly desirable to provide apparatus and a method of overcoming these problems and disadvantages.
It is an object of the present invention to provide a new and improved vertical multiple stage oven.
It is another object of the present invention to provide a new and improved vertical multiple stage oven with multiple heating stages which can be accurately controlled.
It is still another object of the present invention to provide a new and improved vertical multiple stage oven with a transport system that is clean and can be easily compensated for changing lengths.
It is yet another object of the present invention to provide a new and improved vertical multiple stage oven incorporating a plurality of heating stages within a single housing.